中国海洋大学董璐团队最新的研究揭示了高分辨率CESM1对东亚夏季风的改进模拟及其原因。2024年10月8日，国际知名学术期刊《大气科学进展》发表了这一成果。

据悉，基于高、低分辨率群落地球系统模型第1版(CESM1)和耦合模式比对项目第6阶段(CMIP6)的模拟，研究比较了东亚夏季风(EASM)的年际变化。

研究人员称，EASM年际变率表现为北太平洋西部反气旋(WNPAC)环流异常，以及在北太平洋西部上空为负的南叶和Meiyu-Baiu地区为正的北叶的偶极子降雨模式，高分辨率CESM1和CMIP6模式较好地再现了这一特征。高分辨率模式的改进主要是由于，风异常对气候温度梯度的暖温平流的模拟效果较好。热带印度洋的海表温度(SST)正异常是高分辨率模式中以WNPAC为特征的风异常改善的关键。

热带印度洋温暖的海温异常通过触发开尔文波对降水增加引起的增强热释放的响应，加强了西太平洋副热带高压。基于混合层热收支分析，高分辨率CESM1中西印度洋上的SST异常与赤道偏东风异常有关，该异常减少了地表蒸发和上升流。研究结果强调，更好地模拟海气反馈和西印度洋上的海洋中尺度涡，是改善高分辨率CESM1模拟EASM年际变化模拟的关键。

附：英文原文

Title: Improved simulation of East Asian summer monsoon in the high-resolution CESM1 and its causes

Author: Yingshuo Xiang, Lu Dong, Fengfei Song, Lixin Wu, L. Ruby Leung, Shengpeng Wang, Enze Dong, Hong Wang

Issue&Volume: 2024-10-08

Abstract: Based on the high- and low-resolution Community Earth System Model version 1 (CESM1) and the corresponding simulations from the Coupled Model Intercomparison Project Phase 6 (CMIP6), we compare the interannual variability of the East Asian Summer Monsoon (EASM). The EASM interannual variability is characterized by the anomalous Western North Pacific anticyclone (WNPAC) circulation and the dipole rainfall pattern with a negative southern lobe over the Western North Pacific and a positive northern lobe along the Meiyu-Baiu region, which is better reproduced by the high-resolution CESM1 and CMIP6 models. The reason for the improvement in the high-resolution models has been attributed to the better simulation of the warm temperature advection from the wind anomalies on the climatological temperature gradient. Positive sea surface temperature (SST) anomalies over the tropical Indian Ocean are the key to the improved wind anomalies featuring a WNPAC in the high-resolution models. The warm SST anomalies over the tropical Indian Ocean strengthen the WNPAC by triggering a Kelvin-wave response to the enhanced heat release induced by the increased precipitation. Based on the mixed-layer heat budget analysis, the warm SST anomalies over the western Indian Ocean in the high-resolution CESM1 are tied to the anomalous easterly wind along the equator, which reduces surface evaporation and upwelling. Therefore, the better simulations of air-sea feedback and the oceanic mesoscale eddy over the western Indian Ocean are the key for the improved simulation of the EASM interannual variations in the high-resolution CESM1.

DOI: 10.1007/s00376-024-4229-0

Source: http://www.iapjournals.ac.cn/aas/article/doi/10.1007/s00376-024-4229-0